Studies of somatostatin, cortisol and beta-endorphin in relation to affective and other neuropsychiatric disorders have continued. Additionally, in vitro hybridization studies have been performed to determine the effects of gonadal steroids on receptor ontogeny. Findings consist of the following: Somatostatin - We have completed analysis of 30 hour CSF studies in ten patients and ten controls, with evidence for decreased CSF somatostatin in patients that further decreases following ECT. Additionally, 84 additional samples from Alzheimer's patients were analyzed to further explore the relevance of low CSF somatostatin in this patient group. Cortisol and Beta Endorphin - No diagnostic group-related nor menstrual cycle-related differences were observed in ten PMS patients and ten controls phlebotomized across the menstrual cycle. In situ - The following have been observed: 1) Acute developmental stage- dependent regulation of GABA alpha-2 subunit mRNA and protein four hours following injection of testosterone; 2) Sexual dimorphism in alpha-5 and alpha-2 subunit message expression; 3) Gender dependent, developmental stage-dependent, and brain region-dependent reversal of sexual dimorphisms in GABA receptor subunit expression by androgen receptor blockade; 4) Significant changes of 5-HT2A mRNA expression and receptor binding in pregnant rats compared with female controls.